Renewable energy is energy derived from natural resources that can be replenished, such as sunlight, wind, rain, tides, and geothermal heat. The demand for renewable energy has grown substantially with advances in technology and increases in global population. Although fossil fuels provide for the vast majority of energy consumption today, these fuels are non-renewable. The global dependence on these fossil fuels has not only raised concerns about their depletion but also environmental concerns associated with emissions that result from burning these fuels. As a result of these concerns, countries worldwide have been establishing initiatives to develop both large-scale and small-scale renewable energy resources. One of the promising energy resources today is sunlight. Globally, millions of households currently obtain power from solar photovoltaic systems. The rising demand for solar power has been accompanied by a rising demand for devices and materials capable of fulfilling the requirements for these applications.
Harnessing sunlight may be accomplished by the use of photovoltaic (PV) cells (solar cells), which are used for photoelectric conversion, e.g., silicon photovoltaic cells. PV cells are relatively small in size and typically combined into a physically integrated PV module (solar module) having a correspondingly greater power output. PV modules are generally formed from 2 or more “strings” of PV cells, with each string consisting of a plurality of cells arranged in a row and electrically connected in series using tinned flat copper wires (also known as electrical connectors, tabbing ribbons or bus wires). These electrical connectors are typically adhered to the PV cells by a soldering process.
PV modules typically comprise a PV cell surrounded by an encapsulant, such as generally described in U.S. Patent Publication No. 2008/0078445 (Patel et al), the disclosure of which is incorporated herein by reference. In some embodiments, the PV module includes encapsulant on both sides of the PV cell. Two panels of glass (or other suitable polymeric material) are positioned adjacent and bonded to the front-side and backside of the encapsulant. The two panels are transparent to solar radiation and are typically referred to as front-side layer and backside layer, or backsheet. The front-side layer and the backsheet may be made of the same or a different material. The encapsulant is a light-transparent polymer material that encapsulates the PV cells and also is bonded to the front-side layer and backsheet so as to physically seal off the cells. This laminated construction provides mechanical support for the cells and also protects them against damage due to environmental factors such as wind, snow, and ice. The PV module is typically fit into a metal frame, with a sealant covering the edges of the module engaged by the metal frame. The metal frame protects the edges of the module, provides additional mechanical strength, and facilitates combining it with other modules so as to form a larger array or solar panel that can be mounted to a suitable support that holds the modules at the proper angle to maximize reception of solar radiation.
The art of making photovoltaic cells and combining them to make laminated modules is exemplified in, for example, the following U.S. Pat. No. 4,751,191 (Gonsiorawski et al.); U.S. Pat. No. 5,074,920 (Gonsiorawski et al.), U.S. Pat. No. 5,118,362 (St. Angelo et al.); U.S. Pat. No. 5,178,685 (Borenstein et al.); U.S. Pat. No. 5,320,684 (Amick et al); and U.S. Pat. No. 5,478,402 (Hanoka). The teachings of those patents are incorporated herein in their entirety.